How do I use DNA-genealogy?
DNA genealogy makes it possible to research family trees using the latest resources. It facilitates very fast and accurate research into your family history, whether as your first venture into genealogical research or to supplement conventional genealogy. Where conventional genealogical research involves studying birth, marriage, and death certificates, a saliva sample is all that is needed for DNA genealogy.
What is DNA?
DNA stands for deoxyribonucleic acid. Chromosomes are made of DNA, which contains the genetic instructions for all the functions and substances of the body. DNA resembles a spiral staircase and each level is formed from two bases. There are four different bases: guanine, thymine, cytosine, and adenine. 99.9% of the DNA is identical in all people. The remaining 0.1% is the source of individual differences (such as eye colour, certain risks of disease, or deviations with no known function).
The entire DNA of a person is called the genome. We have inherited the genome from all our ancestors. It is re-combined in each generation from the genetic make-up of our parents.
There are only two areas where the DNA is not re-combined:
1. in the Y chromosome, which is passed on from father to son, and
2. in the mitochondrial DNA, which all children inherit from their mother.
Basically, the Y-chromosome and mitochondrial DNA are passed on from one generation to the next unchanged. However, random changes – or mutations – take place regularly. All the descendants of a line will inherit this mutation. When the same mutations are discovered during a comparison of two DNA profiles, it is apparent that these people share a common ancestor. Therefore, mutations form the basis for the construction of a genetic family tree.
How can DNA say anything about my Origins?
A comparison of the DNA profile of people from different sections of the population gives us an idea of when and where these sections moved while migrating around the world. Genetic mutations not only mark specific families, but in the course of time also entire sections of the population. If the frequency or occurrence of certain mutations is studied, then the complex family tree of humanity can be divided into single branches.
If a section of the population then migrates or lives in geographic isolation for a long period, meaning there is no genetic exchange with other sections, then separate patterns of mutation develop. Therefore, these patterns only appear in certain regions and sections of the population.
Due to the steady migration of our ancestors, it has also been possible to provide evidence of genetic relationships between different peoples on earth. For example, researchers have discovered remarkable similarities between ethnic groups in India, Oceania, Australia, as well as between Siberians and native Americans.
What will be analysed in a DNA Genealogy Test?
You can imagine mitochondrial DNA or the Y-chromosome as the genetic coat-of-arms of a lineage. Every member of the paternal line carries the same Y-chromosome, like a heraldic stamp. Over the course of time, this stamp is copied over and over again, and the engraving fades, so that the family's coat-of-arms is no longer clearly recognizable. The DNA acquires new mutations, so that the DNA-profiles of close relatives are more similar than those of two men with a common male ancestor who lived 600 years ago.
The Y Chromosome
Chromosomes consist of DNA and proteins. Each cell of the body has in its nucleus 23 chromosome pairs (Exception: egg cells and sperm cells each have 23 individual chromosomes). One of these pairs is the sex-chromosome pair. Women have two X-chromosomes, men an X- and Y-chromosome. The Y-chromosome is passed from father to son unchanged. Every man inherits therefore his genetic coat-of-arms in the male line from his father. In a DNA-Test, certain known DNA sequences (markers) are looked for. These markers are referred to as DYS and have different gene variants (alleles). The alleles are identified with numbers, which recapitulate the number or repeating sequence segments of that marker.
Every member of the paternal line carries the same Y-chromosome, like a heraldic stamp. Over the course of time, this stamp is copied over and over again, and the engraving fades, so that the family's coat-of-arms is no longer clearly recognizable. The DNA acquires new mutations. The DNA-profiles of two closely related men therefore are much more similar, than the profiles of two men, whose common ancestor lived 600 years ago. The higher the number of matching markers, the closer is the familial relationship between two men. Since it is only a high number of shared markers that indicates a familial relationship, a test examining several markers is needed in order to distinguish relatives from genetically similar lineages.
The mitochondrial DNA
Mitochondrial DNA (mtDNA) is found in every cell, but also outside of the nucleus in the so-called mitochondria. This mtDNA is a ring-shaped, double-stranded DNA molecule and consists of 16,569 base pairs with 37 genes. Since mtDNA evinces a higher rate of mutation than the DNA in the nucleus and is only passed on by the mother, it is a useful tool for researching human ancestry. It is predominantly in two regions of this DNA, the hypervariable regions (HVR) that the mtDNA contains a multitude of patterns. These enable us to clearly differentiate the individual lineages. The mtDNA is passed on intact from mother to child. All people–men and women alike– inherit their mtDNA exclusively from their mothers. Our maternal lineage is therefore represented by our mtDNA.
A mtDNA-test analyses specific regions of the mtDNA. These regions are HVR1, HVR2 (hypervariable regions) and CR (coding region). The results will then be compared with the Cambridge Reference Sequence (CRS). The CRS, a standardized sequence of mtDNA, constitutes the comparative standard for the representation of mtDNA results. This enables us to display mtDNA profiles with some hundred single bases clearly arranged. Only the deviations from this standard sequence are shown in the result. The various deviations enable us to make a definitive statement about the degree of familial relationship between two people. The deviations from the CRS are named for their location and the mutated base: e.g. 16126C means that there is a C instead of the expected T we find in the CRS at location 16126. As on the Y-Chromosome also on the mtDNA mutations happen, which causes to closely related persons to have a more similar profile than relatives of a high degree. The more regions of the mtDNA coincide between two persons, the closer they are related.
What will I know after a DNA-Genealogy-Test?
A genealogy test tells you from which haplogroup you descend (tribe from primeval times), from which ancient tribe from ancient times (Celts, Vikings, Jews, etc.) your ancestors came and in which region your DNA profile is typical. DNA genealogy also enables you to find 'genetic cousins', i.e., people with whom you share common ancestors. By exchanging information such as family tree records with your 'genetic cousins', you broaden your knowledge of the history of your family.
What data provide a basis for your results?
Identification of your genetic origins (haplogroup and ancient tribe) is based on scientific analysis in the areas of genetics and anthropology. Certain DNA mutations (markers) define the various populations. Your DNA profile enables us to identify the ancient tribe you belong to. Each new scientific discovery in these fields supplements the existing data, meaning we always keep you up-to-date with the latest state of research. For searching for relatives, your DNA profile is compared with the DNA profile of all the other people in our database. You are shown who corresponds with you genetically. These 'genetic cousins' share a common ancestor with you. Depending on the degree of the genetic match, it is a closer or more distant relative. In the online result, you will also find a table for calculating the degree of relationship. In your Online-Results, you will receive not only extensive information about your haplogroup and your indigenous people group, but you can also read all of the genetic studies or read detailed answers to questions posted in our forum.
How can I research my surname?
In a surname project an investigation of the biological relationship between men with the same or similar surnames is conducted. This enables you to find people with whom you share ancestors and exchange information (e.g. the family tree). Since the Y-chromosome is usually passed on in the same way as the family name, a person can compare his Y-value with a person sharing the same name and the family tree can be checked. Starting a surname project or joining an existing one is free of charge. We only need a short description of your project, as well as the email address of its administrator, and the project will be immediately posted on our website. Surname projects are a good example of the combination of traditional ancestor research with DNA-Genealogy. Where traditional research yields information about the origins of a family name, DNA-Genealogy allows you to learn who belongs to which lineages.
How can I find more relatives?
The database of iGENEA/FamilyTreeDNA is the largest DNA Genealogy Database in the world and is also the fastest-growing. Since your access is not time-limited, you will find more and more relatives even months and years after your analysis. Additionally, you will have the opportunity to find even more relatives through a surname project or haplogroupproject.